This is one of the items that we are looking into. But we are looking at it from different angles. We are investigating on-prem backup as backup in the cloud. However, there is no white smoke coming out of the chimney

This is something we are also looking for. We have a client that is considering Azure Files & Azure Files Sync, and wants to retain all backups forever. Native Azure Backup does not have the ability to retain backups forever. It has a 10 year maximum.